14 



by the handful without admixture with the four other 

 crustaceans (Daphnia, Cyclops, Sida and Cypris). The 

 Podophyra cyclopum (Diesing) is frequently found as 

 an ektoparasitical animalcule on the whole body of the 

 Cycl. coronatus, and C. quadricornis. It belongs to a 

 very simple organized family of the class Infusoria. 



(AciNET^E, SUCTORI^E.) 



By placing and pressing several specimens of Daphnia, 

 and also of the Cypris-larvae between two glass-covers 

 under the microscope, I found, but seldom during the last 

 Spring, (1871) a very interesting animalcule of a very low 

 organization, the parasite Gregarina. The 

 wood-cut seems to show an Infusorial in divi- 

 sion, but it has no contractile vesicle, (Vacu- 

 ole) and no mouth, etc., only a nucleus-like 

 spot on each elongated side of its very elastic 

 body. The small wood-cut exemplifies two 

 Gregarines in Conjugation. Through this very conju- 

 gation and confoundation, the protoplasm a of their bodies 

 is subdivided into innumerable little cells, called Pseudo- 

 navicultE, by a kind of internal budding of cells from 

 the protoplasma. At a certain time, when these so 

 encysted Gregarines have grown larger, the external 

 cell-body (epidermis) breaks, and scatters the Pseudo- 

 naviculse throughout the water, or as a guest in the 

 intestine of a Daphnia or Cypris, where the Gregarine 

 occurs. The minute organisms which serve as food for 

 other crustaceans, etc., grow larger in their intestines, 

 and the same process will begin again. Another wood- 

 cut has been made by way of comparison of a Grega- 

 rine, which generally is found in the tractus intetestinalis 

 of Blatta Americana (cock-roach) in the common earth 

 worm, also in almost all insects, especially in Coleoptera 

 The encysted Gregarina Blattje has nearly the same 

 form as the encysted and conjugated Gregarine with 



